I have a sister to your truck. It starts and runs, but I have too many of them to try to keep the brakes maintained.

https://plus.google.com/u/0/1126369...1091222818&oid=112636930370126476644

A lot of the body parts are the same on Chev as GMC as well as the transmission and rear. Engines are totally different. I would certainly buy a GMC book.

http://www.faxonautoliterature.com/Search.aspx?c=182016